Driver Skills vs. Acquired Data

1/13Successful drivers need to understand the keys they get from dataacquisition. Driver David Reutimann looks over the computer screen inhis pit cart during a practice session in 2005.

As racers, we tend to be tweakers with lots of focus placed on the racecar (modifying, adjusting, and so on). However, racing is a sport, andit's a sport because it is a contest of one person's skill againstanother's. Many people think it is the skill of building a better racecar, which does play a part, but ultimately it is a test of the driver'sracing skills.

Many racers fail to understand these specific skills or have an egoproblem that interferes with believing they can improve. Drivers whoadamantly say, "If I just had more money or a better setup, I could win"and fail to look at other possibilities typify this situation. The truthis, most wins are distributed among a few drivers at each track, andonly on rare occasions will someone else win. Why? Simply better driverskills!

Once you embrace the importance of driver skill and improving it, youtypically find bigger gains in speed than anything you can legally bolton the race car. So get comfortable, open your mind, and read on to seehow new concepts, technology, and developing specific skills can make ahuge difference in your racing results.

300 Percent Concept

2/13<b>Graph 1</b> - This is a throttle graph. The scale on the left side represents thepercentage of throttle from 0 to 100 percent. The bottom scale is theelapsed time from the start/finish line as the race car completes a lap.The blue line shows how the driver controlled the throttle getting in,through the corners, and back to wide open on the straights.

An idea gaining popularity in professional racing is the "300 Percent"concept. This is actually three 100 percent pieces that work togetherand create the final performance results.

The first part of this concept is the race car's capability. Say you useregular gas, and your car is 500 pounds over minimum weight. If you raceagainst someone who is burning alcohol, has 100 more cubic inches, andis at the minimum weight, then obviously there is a big disparitybetween the cars. In this case, your car may only be 65 or 75 percent ofthe other car when it comes to performance capability. However,division/class rules tend to bring the cars closer together.

Most of the cars in a division are usually within 10 to 15 percent ofeach other (including the minor cheaters), and they get closer togetherthe farther you move up the ranks. For example, if you were to test allthe Nextel Cup cars at a place such as Martinsville, you may find theyare all within 2 or 3 percent of each other.

Another part of this concept is the driver's skill. However, unlike therace cars, drivers vary widely in skill levels. It is common at thelocal level to see a driver with an 85 or 90 percent skill levelcompeting against a 50 percent skill-level driver. In such a case, evenif the lower skilled driver had the better race car, the higher-skilleddriver would place higher on a consistent basis.

The last piece is the driver's performance on any given day. Everybodyhas good days and bad days. A death in the family, divorce, or even theflu can throw you off your game. So, on a great day, you could performat 100 percent of your skill level and on a bad day you perform at alower percentage of your given skill.

Technology to the Rescue A very basic fundamental that all engineers andscientists live by is, "You can't have improvement without measurement."This is where technology fills the bill. Race car data acquisition isnothing more than an electronic measuring system, which often isassociated with the first 100 percent of the 300 Percent concept. Thesecrets you will learn in a few moments will show how data acquisitionis crucial for improving the other 200 percent.

It is important to measure and record what the driver is doing becausewhat may feel fast in the seat isn't always fast on the stopwatch.Often, the exact opposite is true. This may sound odd, but it has beenproven hundreds of times with data acquisition. Simply evaluating whatwas measured and making conscious changes on the driver's part willresult in improvements that are nearly impossible to achieve via theseat-of-the-pants method.

Fortunately, it doesn't take an elaborate or expensive data system fordriver development. The system will, however, need a throttle sensor, asteering sensor, g-force, and vehicle speed sensors. Budget and basicdata acquisition systems typically have these sensors, but if you pickup a used system or homemade system (which are starting to flourish),make sure these sensors are included.

How to Improve Throttle Control

3/13<b>Graph 2</b> - Sometimes it is easier to interpret racing graphs when displayed in feetfrom the start/finish line rather than time. To read this graph, startat the left side, which represents the beginning of the lap. Moving tothe right at roughly 250 feet past the start/finish line, the driverlifts for the corner. At roughly 600 feet, the driver gets back on thethrottle. Following the blue line in this fashion, you know exactly whatthe driver was doing with the throttle and where he was on theracetrack.

As a driver, you may think you are in total control of your body, butmany times this is not the case. In testing, it has been found that adriver will say, "I never lifted that lap," but when you check the data,this is not the case. Sometimes there seems to be a brain-to-footdisconnect, as if the foot has a mind of its own. This is why manycrewchiefs laughingly call data systems "The Lie Detector."

To illustrate this concept, try this experiment with a chair, a piece ofpaper, and a pen. Do it as you read these instructions: Sitting in achair, straighten your right knee slightly so your foot is a few inchesoff the floor. Now, rotate your foot in a circle such that your toes arerotating in clockwise pattern.

Keep your foot rotating, write the number 6 on the paper, then quicklylook at your foot. Which direction is it rotating? Were you aware of anychange? Now, are you sure you know exactly what your foot is doing onthe throttle in the race car? Another popular phrase with crewchiefs is,"What did the data show?"

Using data acquisition, graphs can be constructed to display throttleposition all the way around the track. Watch for specific patterns whenreading (interpreting) data graphs for throttle skills. Often, thepatterns will get nicknames such as "cliffs versus roller coasters" and"pancakes versus high valleys."

4/13<b>Graph 3</b> - Specific numbers for any point along a throttle graph can be displayedon your computer. Clicking anywhere along the graph, a marker line(green in this example) will appear. This software then displays thethrottle position near the top right of the screen (21.0 percent) andthe distance to the far right of the lower scale (323 feet).

An example of throttle cliffs can be seen in Graph 1. This graph showsthat the driver completely dropped the throttle in roughly 1 second whenentering Turn 1. Likewise, in Turn 3, the driver dropped the throttle inroughly 0.7 second. Especially on pavement, this tends to be less thandesirable throttle control.

Another example of undesirable throttle control is the pancake followingthe cliff. Graph 2 shows the same data but displays distance rather thantime on the bottom scale. This data shows the driver is completely offthe throttle for roughly 250 feet in each corner. Oftentimes, thepancake is a result of the throttle cliff. Suddenly dropping thethrottle upsets the car's balance, and the driver must wait longer toget back on the throttle.

Graph 3 represents a different driver with good throttle habits. You cansee the throttle pattern looks much more like a roller coaster than thecliffs in the previous two graphs. Also, notice the driver manages tokeep the throttle open between 20 and 25 percent in the middle of thecorners. These high valleys will result in more mid-turn speed than thepancakes in the previous graphs. For you sharp-eyed graph readers, youwill also notice the driver is lifting well before the start/finishline.

5/13<b>Graph 4</b> - A helpful feature in data acquisition software displays information fromseveral laps at once. This graph shows the throttle control for threelaps. Each color represents a different lap.

Data acquisition helps the driver develop consistency. Graph 4 shows athrottle pattern for several laps. Sometimes, when using less throttleat the slowest point of a corner, the driver will feel the need to startapplying more throttle while exiting the turn.

However, this can end up with a wheelspin or a handling conditionrequiring the driver to modulate the pedal. As a result, the lap timessuffer (see blue line). This illustrates why it is important for thedriver to be a robot and do exactly the same thing lap after lap.

Finally, a concept popular with professional drivers is what they call"sweet spots." These are specific spots (or reference points) around theracetrack for specific throttle control (lift points, hold points, andso on). The objective is to find what points yield the best lap times.

Because the data system is measuring the distance around the racetrack,it is easy to locate different points the driver can visually identify(sign, light pole, and so on) and see what lap times or segment timesare associated with different points.

There are many other aspects of throttle control that can be improvedwith data acquisition, too. Remember, however, what feels fast in theseat is not always fast on the stopwatch.

How to Improve Steering Control

6/13<b>Graph 5</b> - When reading data graphs, it is important to recognize general patterns.On an oval track, there are two main steering motions (one for each endof the track). Little wiggles in the line tend to come from bumps in thetrack or vibrations. Big jags or spikes in the line are a result of thedriver's input on the steering wheel.

One of the first items to consider with steering is whether you are inoffense or defense mode. This is a clear concept in other sports, but itis often overlooked in racing. On the defense side of the game, ifsomeone drives across your line entering a turn, an adjustment must bemade.

Another example of defense is when you are "off-line," fighting forposition. The lap times nearly always suffer when driving in defensemode. Offense mode occurs when you are clear of traffic and you candrive the fastest line around the racetrack. The steering controldiscussed here will only address the offense mode.

Conversations about driving often address the "line" (the path you wantthe car to travel), but never how to manipulate the steering wheel toachieve a given line. Consequently, some drivers are not aware they arecausing a handling problem (or the difficulty maintaining a desiredline) because of their steering skills.

Graph 5 is an example of a driver who mistimes the steering for thecorners. The steering trace for both corners has a leading spike ratherthan a rounded plateau. The leading spike is where the driver is tryingto get to the bottom of the track.

7/13<b>Graph 6</b>- With data graphs, it is easy to spot bad driver habits. A steering tracewith lots of wiggles is often a sign of an overactive driver.Such steering habits aggravate handling or can induce handling problems.

In this case, the race car gets to the bottom quickly, and the drivermust reduce the steering for the remainder of the turn or end up in theinfield. The steering input for turns 3 and 4 shows the timing wasmistimed badly enough on this lap; a second big "cut" on the steeringwheel was necessary to finish the corner.

Sometimes, drivers are not aware of what their hands are doing or howthey are responding to the feel in the steering wheel. Interestinglyenough, not all drivers respond the same for a given feel in the wheel.

Some drivers appear to be force oriented (increasing/decreasing wheelangle to maintain a specific torque on the wheel). Other drivers aredisplacement oriented, turning the wheel to a specific angle while beingunaware of the speed at which the wheel was turned. Here, again, iswhere data acquisition can do wonders in developing steering skills.

8/13<b>Graph 7</b>- shows a smoother steering graph and is a sign of adisciplined driver.

An example of force responding to wheel feel can be seen in Graph 6.Here, the data shows what is often called "sawing on the wheel." You cansee a big overall hump on the graph for each turn, but there are lots ofwiggles in the line, indicating a back-and-forth motion on the steeringwheel. Graph 7 shows the same driver after the "sawing" was brought tohis attention via the data acquisition. Here, you notice the trace ismuch smoother.

Also, when the driver made a conscious effort to change the steeringinput, the car settled down and the lap time went from 21.129 in thefirst example to 20.846 in this example.

While smoothing out your steering motion sounds quite easy, in reality,it is very hard to do. The previous examples are from a full-timeprofessional driver on a half-mile racetrack. Graph 8 is a weekenddriver (with several championships to his credit) on a half-mile track.Notice here there are fairly big jags in the steering trace.

Another example of a weekend racer is displayed in Graph 9. This, too,is a champion racer with many pole positions and wins to his credit.Notice this steering trace is fairly jagged, too. As mentioned in the300 Percent concept, a track champion typically has better skills than aracer in the middle or back of the pack, but you can see a full-timeprofessional racer has better skills, yet.

How to Improve Braking Control

9/13<b>Graphs 8 & 9</b> - These steering traces show a lot of activity, which is common for dirttrack drivers even after they switch to pavement racetracks (as thisexample illustrates). An awareness of your hands is very important.Sometimes, hands short-circuit directly to the seat and try to correctevery little wiggle or bump the car encounters.

Braking control tends to be more difficult than throttle or steeringcontrol. One of the reasons braking is so difficult is there areactually two brakes on a race car. Everybody is aware of the brakepedal; however, the engine is also a brake.

The total slowing of the race car can be a result of the engine brakeand/or friction brakes. It's the blending of engine brake and foot brakethat makes this skill more challenging and the reason "left foot"braking typically yields the best results.

Most drivers are unaware of how they use the brake pedal. Some may beable to identify using a large amount of pedal force for a shortduration or a lower pedal force for a longer duration, but beyond thatthey are typically unsure of what their feet are doing. Just likethrottle and steering control, the minutia of highly skilled brakingseldom come naturally and must be developed.

10/13<b>Graph 9</b>

Pressing the pedal to reach the maximum force is an important skill. Toillustrate this point, examine Graph 10. Here, you will see a very quickand smooth increase in force to a peak value. Also, the peak brakingforce for both ends of the racetrack are virtually the same. This is askill many weekend drivers lack (this graph is from a full-time pro).Oftentimes, you will find brake force varies from lap to lap and inevery turn. The ability to repeat the same force is paramount inimproving lap times and solving setup conditions with your chassis.

11/13<b>Graphs 10 and 11</b> - The graph on the top shows brake pressure with a very desirable pattern.While this may look simple, it is very hard to actually achieve. Thegraph on the bottom has many jags on the release side of the brakingaction. It takes a conscious effort and practice not to have a brakepressure graph that looks like this example.

Another braking skill is the release. In Graph 10, you can see that thedriver had a steady and uniform release of the brake. However, in Graph11, this driver did not release the brakes smoothly, which many driversdo without realizing what they have done. This can lead to body rockingor a yaw oscillation (i.e., bad handling). Typically, chassis setupreceives the blame for this condition rather than the real source--thedriver!

Again, combining brake-pedal motion with the throttle motion is key tomastering braking skills. You can slow down by simply taking your footoff the throttle, or slow down faster by pressing the brake pedal. Bothactions work together for the total slowing, and data acquisition can beused to measure the overall result, too.

One concept used to measure overall slowing is sometimes called"Deceleration G (force) Time Integral" (DGTI for short). The red traceon Graph 12 can be used to illustrate the DGTI concept. The foundationof this concept is the total slowing can be compared to a given force(say 1 g) for a specific amount of time.

12/13<b>Graph 11</b>

In Graph 12, there is a red box just to the left of the crosshairs inthe middle of the screen. The DGTI for this turn is 2.097 (or theequivalent of slowing down at 1 g for 2.097 seconds). Notice that eventhough the brake pedal was released (blue trace), the red line is stillclimbing (increasing the DGTI). This is due to the lack of throttle(engine braking--green trace).

Even partial throttle can slow your race car! Once the throttle headsback toward 100 percent, the red line levels off for the final value ofdeceleration. To further illustrate this point, in Turns 3 and 4, thedriver used no brake and only lifted the throttle. Notice that the redtrace climbs in this condition, too.

The DGTI may be a little difficult to comprehend at first, but once youget the idea, it is an incredibly powerful tool for developing brakingskills and improving lap times.

Summary

13/13<b>Graph 12</b> - At first glance, this is a very busy graph, but it is an incrediblypowerful tool for developing braking skill and improving lap times. Theblue line is the brake pressure and the green line is the throttleposition. The red line is a measure of how much the car was slowed bythe combination of lifting and braking.

In the past, some drivers were said to be naturals. Some excelled intheir racing career and some never made it out of the local level. Itwas also believed that a struggling driver just needed more seat time toimprove. However, practice doesn't make perfect, only perfect practicemakes perfect. Otherwise, just practicing may reinforce bad habits andgood race driving skills may never be developed.

Now, with the introduction of affordable data acquisition, even localracers can develop the skills necessary to win or move up the racingladder. You have now been exposed to some specific race driving skillsthat should be goals for your driver to try to achieve in the seat. Thebonus to approaching racing performance in this fashion is you maydiscover there is nothing wrong with your race car's setup/power or thatmany of your setup/power problems disappear with the development of gooddriving skills.